1. Field of the Invention
The present invention is generally in the field of semiconductors. More particularly, the invention is in the field of fabrication of flash memory cells in semiconductor dies.
2. Background Art
Flash memory and logic circuitry are widely utilized in electronic systems in cell phones, computers, and other electronic devices. Flash memory, which can include multiple flash memory cells, and logic circuitry, which can include multiple field effect transistors (FETs), can be fabricated on separate semiconductor dies. However, it is desirable to integrate flash memory and logic circuitry on a semiconductor die in a system-on-chip (SoC) to achieve increased performance and system reconfigurability. It is further desirable to integrate flash memory and logic circuitry in an SoC using advanced process technologies, such as 45.0 nanometer (nm) and smaller process technologies.
Flash memory cells typically include a floating gate and an overlying control gate, where the floating gate and the control gate can be conventionally fabricated by utilizing a polysilicon process. For advanced process technologies, such as, for example, a 45.0 nm process technology, FETs in logic circuitry can be fabricated by utilizing a high dielectric constant (high-k) metal gate process. However, conventionally integrating flash memory cells, which are fabricating by utilizing a polysilicon process, and logic circuitry, which is fabricated by utilizing a high-k metal gate process, in an SoC can require additional masks and process steps, which can undesirably increase manufacturing cost.